It can be hard to come up with original twists on gaming these days, but somehow indie developers keep finding new, exciting ways to tweak old gaming formulas. From altering the speed of light to a pair of text adventures that’ll get your blood pumping as fast as any AAA shooter, this week’s free games are all about unusual game mechanics.

Asphyx

Asphyx is a platformer where you decide when you die. Your character can survive underwater only as long as you the human player can physically hold your breath, because the moment you gasp for air you should press the escape button and admit you’ve drowned. While there’s nothing forcing you to play it without cheating this novel “game mechanic” adds an extra layer of intensity to the game’s many underwater sections.

Text Based Multiplayer Shooter

Text Based Multiplayer Shooter is a surprisingly fast-paced game considering it’s, well, text-based. With only a few bullets and a list of exit directions to guide you, the game drops you into a maze filled with other players and tasks you with looking around to find and fire on your enemies. Since each step of this has to be typed out like you’re playing a text adventure though the game becomes a bit of a typing reaction speed test just as stressful as the mouse reaction time you’ve needed to hone in a traditional multiplayer shooter.

A Slower Speed of Light

A Slower Speed of Light is an odd project, sort of half game and half physics thought experiment. The game is a product of the MIT Game Lab and the goal is to help players understand relativistic effects that occur close to the speed of light. Your tasked with collecting 100 little widgets but each time you do the speed of light slows down, causing increasingly odd effects as you try and travel through the world. At the moment the game mechanic parts of Slower Speed of Light are kind of bare-bones, but since the game is being released with open source code the potential is also there to build a more complex game on top of the engine.

Panic!

Panic! is certainly good at instilling the feeling in its title. A text adventure about being trapped in a burning building, the game gives you just six seconds to make each new decision, often not enough time to even fully read the description in front of you. With just the simplest of interfaces and with no images at all the game manages to evoke the actual panic of a hectic situation where every choice counts.

Hindsight

Hindsight starts off as a relatively simple game. You press space to get your block moving up or release it to let it fall down, and you try to avoid the circles scattered about the level. The complications come in when you reach the other end of the level and switch directions only to find the path you just traveled is now littered with new dots. As you flip back and forth through the game’s small area of play you gain points but the game’s mechanic gets more intense as well. Before long you’ll be leaving fairly solid paths that stick around almost indefinately; good luck!

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David Daw has studied the history and future of television and has a master's in Broadcast and Electronic Communication Arts from San Francisco State University along with a BA in genre fiction from NYU.